We should not, however, imagine, that the learned alone destroy their health by mental labour; it is of no consequence what the object is that engages the mind, if it applies a considerable time and with earnestness, it wastes both its own strength and that of the body. Kings, senators, ministers, ambassadors, and all those concern’d in the administration of public affairs, are subject to the same unhappy fate which the learned deplore, if they labour with equal assiduity in transacting public affairs, as the learned in perusing books. But it is their happiness, that, in the various business and dissipation of their places, they are oblig’d often to quit their closets, and even against their wills are, by a salutary necessity, compell’d to take frequent exercise: the chief use of this is, that it admirably prepares the blood for the generation of fresh animal spirits, and in the same time it brings a greater quantity of blood to the secerning organs, and so restores what thought had exhausted, and frames new instruments for the thinking mind. But nothing can force the studious from their books, and they are quite enervated by inaction: to palliate which you will perhaps bring some examples of men who have liv’d to a great age, though they used but little or no action. There are but few men; but you will, I doubt not, bring many women. Take notice, however, that, though they had not much muscular motion, they had many other helps, by which nature promotes the circulation of the blood, _viz._ an agreeable stirring of the passions, which excites, and does not destroy; a constant chearfulness and eternal loquacity, and other assistances of a similar nature: they likewise use but little food. The case is quite different with the learned: they do not live with the same sobriety; and therefore it is no wonder that they enjoy their health worse than any other class of men.